Rotary pressure vessel



Dec. 2, 1969 J. F. cox JR ROTARY PRESSURE VESSEL 2 Sheets-Sheet 1 Filed Feb. 2, 1968 IINVENTORI JULIAN F. COX, JR.

ATTORNEYS United States Patent O 3,481,050 ROTARY PRESSURE VESSEL Julian F. Cox, Jr., Newport News, Va., assiguor to Newport News Shipbuilding and Dry Dock Company, Newport News, Va., a corporation of Virginia Filed Feb. 2, 1968, Ser. No. 702,732

Int. Cl. F26b 13/18; F28f 5/02 US. Cl. 34-124 18 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION The present invention relates to a new and novel rotary pressure vessel, and more particularly to a Yankee drier or the like having ribs of high thermal conductance on the inner periphery thereof.

The present invention is particularly directed to Yankee driers employed for drying a web of paper which is run over the smooth outer surface of the Yankee drier shell to be smoothed, dried or glossed by the application of heat, and in some instances pressure.

Steam is admitted under pressure into the interior of the shell, and the shell is particularly designed to transfer the heat of condensation through the shell to the web being treated. Drying of paper and the like in Web form requires high uniformity of heat transfer to the various portions of the shell to obtain the desired results.

It has been proposed in the prior art to provide integral ribs on the inner surface of an iron drier shell. The present invention represents an improvement over this type of arrangement.

SUMMARY OF THE INVENTION In the present invention, a liner is provided on the inner surface of the outer cast iron drier shell, this liner having higher thermal conductivity than the cast iron portion of the shell. This liner is also provided with ribs of certain critical dimensions in order to provide optimum performance of the drier. In a modified form of the invention, separate ribs of high thermal conductivity are secured to the inner surface of the shell.

The provision of such separate ribs serves to increase the rate of heat transfer through the shell, the liner or ribs preferably being made of a substance such as aluminum or copper and the like and being suitably bonded to the inside surface of the outer cast iron shell portion. With this arrangement, it has also been found that the rate of heat transfer is not affected by normal variations in condensate thickness that occur above rimming speed of the drier. Furthermore, since the rate of heat transfer is not affected by variations in condensate thickness, it is not necessary to use complex condensate removal systems as required in conventional drier shells. The ribs also limit the flow of condensate within the drier to a circumferential flow and ensure that no longitudinal flow will occur.

Through the arrangement of the ribs, substantially uniform heat transfer to all portions of the outside surface of the shell is obtained, and at the same time the excellent strength and wear characteristics of the cast iron outer ice shell portion are maintained. The liner and ribs can also serve to strengthen the shell somewhat, thereby adding to the structural rigidity of the construction.

The liner also serves to fill up small pores formed on the inner surface of the cast iron outer shell portion, thereby enhancing uniform heat transfer to a paper web passing over the shell, and further preventing leakage of steam through the outer shell portion. This eliminates the use of plugs in the cast iron drier shell.

The ribs are provided with a particular thickness and are spaced apart a particular distance in order to provide the desired results, the ribs having opposite side surfaces which extend inwardly, the inner surfaces of the ribs being tapered to an apex or of crowned configuration. This apex or crown at the inner portion of each of the ribs aids in shedding condensate from the rib when the drier operates above rimming speed, thereby increasing the rate of heat transfer through the ribs at such speeds.

The liner and ribs may be formed of various materials of high thermal conductivity such as aluminum or copper. These substances are desirable due to their availability and further their ability to adhere to a cast iron outer shell portion in a bonding process.

An object of the present invention is to provide a new and novel Yankee drier or the like of such a construction as to provide an increased rate of heat transfer through the shell thereof.

Another object of the invention is the provision of a Yankee drier or the like wherein the rate of heat transfer is not affected by normal variations in condensate thickness that occur above rimming speeds of the drier.

A further object of the invention is to provide a Yankee drier which affords substantially uniform heat transfer to all portions of the outside surface of the shell thereof.

Yet another object of the invention is the provision of a Yankee drier or the like including supplementary means for preventing leakage of steam through the cast iron outer shell portion thereof, and wherein the overall strength of the construction is increased.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal section through a Yankee drier according to the present invention;

FIG. 2 is an enlarged view of a portion of the structure shown in FIG. 1 illustrating certain details thereof; and

FIG. 3 is a view similar to FIG. 2 illustrating a modified form of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings wherein like reference characters designate corresponding parts throughout the several views, FIG. 1 illustrates a typical Yankee drier construction according to the present invention. A generally cylindrical shell indicated by reference numeral 10 is formed of cast iron or similar material and has a smooth outer peripheral surface. The shell includes spaced ribs 12 which extend substantially continuously circumferentially along the inner portion thereof. A liner 14 formed preferably of aluminum or copper and the like is metallurgically or mechanically bonded to the inner periphery of shell 10, this liner having a plurality of ribs 118 formed on the inner portion thereof, these ribs defined in more detail hereinafter.

A first head 16 is provided at one end of the shell, and a second head 18 is provided at the opposite end of the shell, these heads being suitably secured as by bolts 20 to the shell and forming closures for the opposite ends thereof.

A plate 24 is bolted to head 16 and includes a journal 28 which is hollow and receives an inlet tube 30 through which steam is introduced into the drier. Journal 28 is adapted to be rotatably supported in a suitable conven 3 tional manner. Inlet tube 30 is adapted to feed steam into the interior of a hollow tubular portion 32 integral with plate 24.

A plate 40 is secured by bolts 42 to head 18, plate 40 including an integral journal 44 which is hollow and which receives an outlet tube 46 for removing steam from the drier as hereinafter explained. Journal 44 is adapted to be suitably rotatably supported in a conventional manner. The outlet tube 46 is in communication with the hollow interior of a tubular portion 48 formed integral with plate 40.

The inner ends of tubular portions 32 and 48 are provided with flanges 50 and 52 which extend radially outwardly thereof and which are bolted to one another by bolts 54. A plate 55 is sandwiched between flanges 50 and 52, and is secured in the operative position illustrated. Steam nozzles 56 and 58 are mounted within the outer ends of openings 60 and 62 respectively formed in plate 55, whereby steam introduced through the inlet tube 30 passes through the tubular portion 32 and thence outwardly through openings 60 and 62 in steam nozzles 56 and 58 into the interior of the drier shell.

Means for removing condensate from the interior of the shell includes a support member 70 extending radially outwardly from the flange portion 52 and supporting a longitudinally extending hollow pipe 72 supported at brackets 74 and 76 at the opposite ends thereof, these brackets being mounted upon heads 16 and 18, respectively. A plurality of straws or tubes 78 extend from pipe 72 into the bottom of the grooves provided between adjacent ribs 118 formed on the liner 14, these tubes serving to pick up condensate in the grooves which is then carried to the pipe 72 and thence through a radially extending conduit 80 to the interior of the tubular portion 48.

A second support member 84 extends radially outwardly from flange 52 and supports a hollow pipe 86 at a position substantially diametrically opposite to the previously described pipe 72. Pipe 86 is supported at the opposite ends thereof by brackets 88 and 90 mounted on the heads 16 and 18 respectively. A plurality of straws or tubes 92 extend radially outwardly from pipe 86 into the bottom of the grooves formed between adjacent ones of the ribs 118 on the liner. Condensate received by tubes 92, which, of course, are open at the outer ends thereof, is directed to pipe 86 and thence through a radially inwardly extending conduit member 94 to the interior of the hollow tubular portion 48 whereupon the condensate may pass outwardly through the outlet tube 46.

Referring now to FIG. 2 of the drawings, an enlarged view of the lower portion of the shell shown in FIG. 1 is illustrated wherein certain critical dimensions of the various components are illustrated. As shown in this figure, liner 14 which is formed preferably of aluminum or copper and the like is metallurgically or mechanically bonded to the inner surface of shell 10. This liner defines an inner portion generally of a shape similar to the inner portion of the shell to effectively define a plurality of radially inwardly extending ribs 118, these ribs corresponding in number to the ribs 12 defined by the shell.

This particular modification is directed to shells which have so-called deep ribs formed thereon, deep ribs being defined as those which have a height within the range of approximately 1 to 2 inches. The configuration of the liner as illustrated in FIG. 2 is especially adapted to improve heat transfer for such deep ribbed shells of rotary pressure vessels.

In this form of the invention, the dimension 6 represents the width of a rib of the cast iron shell. The dimension S represents the spacing in a direction extending substantially parallel with the longitudinal axis of the shell of side surfaces of adjacent ribs of the liner at the base or root portion of the ribs. The dimension S represents the spacing in a direction extending substantially parallel with the longitudinal axis of the shell between facing side surfaces of adjacent ribs of the cast iron shell. The dimension L" represents the root thickness of the liner.

The angle 0 represents the slope of the inner surfaces of the ribs of the shell with respect to a line extending substantially parallel with the longitudinal axis of the shell. The inner surfaces 120 of the ribs taper to an apex 122 for the purpose previously described.

The dimension it represents the width of the liner side wall adjacent the inner surface of the associated rib of the shell. The dimension W represents the thickness of the inner wall of the liner. The dimension L represents the height of a rib of the cast iron shell. The dimension L represents the thickness of the cast iron shell.

The angle represents the angle of a rib side surface of the liner relative to a plane extending substantially perpendicular to the longitudinal axis of the shell.

The following table defines the approximate lower limits and upper limits of the various dimensions and angles as described hereinabove.

Approximate Approximate Lower Limit Upper Limit Units 0. 01 1. 25 Inches 0. 00 0. 75 Do. 0. 05 1. 25 DO. 0. 01 0.375 D0. 0. 00 20. 0 Degrees. 0. 001 S/2. 01 Inches. 0. 001 0. 10 D0. 0. 50 2. ()0 D0. 0. 25 2. 50 D0.

0 35 Degrees.

With the dimensions as set forth in the above table, olptilinum performance will be obtained with deep ribbed s e s.

Referring now to FIG. 3 of the drawings, a modified form of the invention is illustrated. The cast iron shell replaces the shell 10 of the previously described modification, shell 130 including a smooth generally cylindrical outer surface 132 and a smooth generally cylindrical inner surface 134. The drier structure is the same as that illustrated in FIG. 1, the straw 92 corresponding to the straw 92 previously described the only difference in the structure being in the configuration of the shell 130 and the manner in which the ribs are provided on the inner portion thereof.

In this latter form of the invention, a plurality of separate and independent generally annular ribs 136 are provided, these ribs being formed of a material of high thermal conductivity such as aluminum or copper. These ribs may be of one-piece construction and are suitably secured to the inner surface of the shell by metallurgically or mechanically bonding the ribs in place.

As shown in FIG. 3, the dimension A represents the thickness of the cast iron shell 130. The dimension B represents the width of individual ribs 136 in a direction extending substantially parallel with the longitudinal axis of the shell. The dimension C represents the space between facing side surfaces 138 of adjacent ones of said ribs, it being noted that these side surfaces extend substantially radially inwardly. The dimension D represents the height of the ribs.

The dimension A for all practical sizes of Yankee driers will lie within a range of about 0.25 inch to about 2.5 inches. The width B of the rib should lie within a range of about 0.25 inch to about 1.50 inches, and with the configuration shown in FIG. 3, wherein no ribs are formed on the shell 130, the optimum value of the distance B is about 1.25 inches.

The distance C should lie within the range of about 0.25 inch to about 1.5 inches, and a spacing of about 0.5 inch is considered to be an optimum spacing.

The dimension D should lie within the range of about 0.25 inch to about 1.25 inches.

It will be noted that the inner surfaces of each of the ribs is tapered to an apex 104, these inner surfaces defining an angle x as seen in FIG. 3 with an adjacent side surface of the associated rib of approximately 15.

With the dimensions as set forth hereinabove, the arrangement has been found to provide optimum performance. It is apparent from the foregoing that there is provided according to the present invention a new and novel rotary pressure vessel such as a Yankee drier or the like having a construction which provides an increased rate of heat transfer through the shell thereof. The rate of heat transfer is not affected by normal variations in condensate thickness that occur above rimming speeds of the drier. Substantially uniform heat transfer to all portions of the outside surface of the shell is afforded. The liner prevents leakage of steam through the cast iron outer shell portion, and further enhances the structural rigidity of the overall drier construction.

As this invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive, and since the scope of the invention is defined by the appended claims, all changes that fall within the metes and bounds of the claims-eor that form their functional as well as conjointly cooperative equivalents are therefore intended to be embraced by those claims.

I claim:

1. A Yankee drier or the like comprising a generally cylindrical shell, a head at each end of said shell forming closures for opposite ends of the shell and including means for journalling the shell for rotation about-its longitudinal axis, said shell having a plurality of spaced radially inwardly extending ribs on the inner portion thereof and extending substantially continuously along the inner portion of the shell in a circumferential direction, said ribs being formed of a material having higher thermal conductivity than the shell portion disposed outwardly thereof, said shell including an outer shell portion, a liner disposed inwardly of said outer shell portion and in contact therewith, said ribs being formed on said liner, said liner having a higher thermal conductivity than said outer shell portion, and the root thickness of said liner being within the range of about 0.01 inch to about 0.375 inch.

2. A Yankee drier or the like comprising a generally cylindrical shell, a head at each end of said shell forming closures for opposite ends of the shell and including means for journalling the shell for rotation about its longitudinal axis, said shell having a plurality of spaced radially inwardly extending ribs on the inner portion thereof and extending substantially continuously along the inner portion of the shell in a circumferential direction, said ribs being formed of a material having higher thermal conductivity than the shell portion disposed outwardly thereof, said shell including an outer shell portion, a liner disposed inwardly of said outer shell portion and in contact therewith, said ribs being formed on said liner, said liner having a higher thermal conductivity than said outer shell portion, and the spacing of side surfaces of adjacent ribs of the liner at the base of the ribs being no more than about 0.75 inch and diverge inwardly therefrom.

3. A Yankee drier or the like comprising a generally cylindrical shell, a head at each end of said shell forming closures for opposite ends of the shell and including means for journalling the shell for rotation about its longitudinal axis, said shell having a plurality of spaced radially inwardly extending ribs on the inner portion thereof and extending substantially continuously along the inner portion of the shell in a circumferential direction, said ribs being formed of a material having higher thermal conductivity than the shell portion disposed outwardly thereof, said shell including an outer shell portion, a liner disposed inwardly of said outer shell portion and in contact therewith, said ribs being formed on said liner, said liner having a higher thermal conductivity than said outer shell portion, and the width of the liner 6 side wall adjacent the inner surface thereof being within the range of about 0.001 inch to about S/2-.01 inch where S is the space between facing side surfaces of adjacent ribs of the shell.

4. A Yankee drier or the like comprising a generally cylindrical shell, a head at each end of said shell forming closures for opposite ends of the shell and including means for journalling the shell for rotation about its longitudinal axis, said shell having a plurality of spaced radially inwardly extending ribs on the inner portion thereof and extending substantially continuously along the inner portion of the shell in a circumferential direction, said ribs being formed of a material having higher thermal conductivity than the shell portion disposed outwardly thereof, said shell including an outer shell portion, a liner disposed inwardly of said outer shell portion and in contact therewith, said ribs being formed on said liner, said liner having a higher thermal conductivity than said outer shell portion, and the angle of a rib side surface of the liner relative to a plane extending substantially perpendicular to the longitudinal axis of the shell is no greater than about 35.

5. A Yankee drier or the like comprising a generally cylindrical shell, a head at each end of said shell forming closures for opposite ends of the shell and including means for journalling the shell for rotation about its longitudinal axis, said shell having a plurality of spaced radially inwardly extending ribs on theinner portion thereof and extending substantially continuously along the inner portion of the shell in a circumferential direction, said ribs being formed of a material having higher thermal conductivity than the shell portion disposed outwardly thereof, said shell including an outer shell portion, a liner disposed inwardly of .said outer shell portion and in contact therewith, said ribs being formed on said liner, said liner having a higher thermal conductivity than said outer shell portion, and the root thickness of the liner is within the range of about 0.01 inch to about 0.375 inch, and wherein the width of the liner side wall adjacent the inner surface thereof is within the range of about 0.001 inch to about S/2-.01 inch where S is the space between facing side surfaces of adjacent ribs of the shell.

6. A Yankee drier or the like comprising a generally cylindrical shell, a head at each end of said shell forming closures for opposite ends of the shell and including means for journalling the shell for rotation about its longitudinal axis, said shell having a plurality of spaced radially inwardly extending ribs on the inner portion thereof and extending substantially continuously along the inner portion of the shell in a circumferential direction, said ribs being formed of a material having higher thermal conductivity than the shell portion disposed outwardly thereof, said shell including an outer shell portion, a liner disposed inwardly of said outer shell portion and in contact therewith, said ribs being formed on said liner, said liner having a higher thermal conductivity than said outer shell portion, and the root thickness of the liner is within the range of about 0.01 inch to about 0.375 inch, and wherein the spacing of side surfaces of adjacent ribs of the liner at the base of the ribs is no more than about 0.7 5 inch.

7. A Yankee drier or the like comprising a generally cylindrical shell, a head at each end of said shell forming closures for opposite ends of the shell and including means for journalling the shell for rotation about its longitudinal axis, said shell having a plurality of spaced radially inwardly extending ribs on the inner portion thereof and extending substantially continuously along the inner portion of the shell in a circumferential direction, said ribs being formed of a material having higher thermal conductivity than the shell portion disposed outwardly thereof, said shell including an outer shell portion, a liner disposed inwardly of said outer shell portion and in contact therewith, said ribs being formed on said liner,

said liner having a higher thermal conductivity than said outer shell portion, and the spacing of side surfaces of adjacent ribs of the liner at the base of the ribs is within the range of about 0.375 inch to 0.75 inch, and wherein the width of the liner side wall adjacent the inner surface thereof is within the range of about 0.001 inch to about S/2.01 inch where S is the space between facing side surfaces of adjacent ribs of the shell.

8. Apparatus as defined in claim 7 wherein the root thickness of the liner is within the range of about 0.01 inch to about 0.375 inch.

9. Apparatus as defined in claim 8 wherein the angle of a rib side surface of a liner relative to a plane extending substantially perpendicular to the longitudinal axis of the shell is no greater than about 35.

10. A Yankee drier or the like comprising a generally cylindrical shell, a head at each end of said shell forming closures for opposite ends of the shell and including means for journalling the shell for rotation about its longitudinal axis, said shell having a plurality of spaced radially inwardly extending ribs on the inner portion thereof and extending substantially continuously along the inner portion of the shell in a circumferential direction, said ribs being formed of a material having higher thermal conductivity than the shell portion disposed outwardly thereof, each of said ribs comprising a separate and independent annular member, said shell including an outer shell portion, and said ribs being secured to the inner periphery of said outer shell portion.

11. Apparatus as defined in claim 10 wherein opposite side surfaces of each of said ribs extend substantially radially inwardly.

12. Apparatus as defined in claim 10 wherein the space between the facing surfaces of adjacent ribs in a direction parallel with the longitudinal axis of said shell is within the range or about 0.25 inch to about 1.25 inches.

13. Apparatus as defined in claim 10 wherein the width of each of said ribs in a direction extending parallel with the longitudinal axis of said shell is within the range of about 0.25 inch to about 1.50 inches.

14. Apparatus as defined in claim 10 wherein the space between facing surfaces of adjacent ribs in a direction extending parallel with the longitudinal axis of said shell is within the range of about 0.25 inch to about 1.25 inches, and the width of said ribs in a direction extending parallel with the longitudinal axis of said shell is within the range of about 0.25 inch to about 1.50 inches.

15. Apparatus as defined in claim 10 wherein said outer shell portion defines a smooth outer peripheral surface, said outer shell portion being formed of cast iron, each of said ribs having opposite side surfaces extending radially inwardly, the space between the facing side surfaces of adjacent ribs in a direction extending substantially parallel with the longitudinal axis of said shell being within the range of about 0.25 inch to about 1.25 inches, and the width of each of said ribs in a direction extending substantially parallel with the longitudinal axis of said shell being within the range of about 0.25 inch to about 1.50 inches.

16. Apparatus as defined in claim 15 wherein said space is approximately 0.5 inch. I g

17. A Yankee drier or the like comprising a generally cylindrical shell, a head at each end of said shell forming closures for opposite ends of the shell and including means for journalling the shell for rotation about its longitudinal axis, said shell having a plurality of spaced radially inwardly extending ribs on the inner portion thereof and extending substantially continuously along the inner portion of the shell in a circumferential direction, said ribs being formed of a material having higher thermal conductivity than the shell portion disposed outwardly thereof, each of said ribs comprising a separate and independent annular member, said shell including an outer shell portion and an inner cylindrical surface, said ribs being secured to and in direct contact with the inner cylindrical surface of said outer shell portion, and each of said ribs having opposite side surfaces extending radially inwardly and including an inner surface which is tapered to an apex.

18. A Yankee drier or the like comprising a generally cylindrical shell, a head at each end of said shell forming closures for opposite ends of the shell and including means for journalling the shell for rotation about its longitudinal axis, said shell having a plurality of spaced radially inwardly extending ribs on the inner portion thereof and extending substantially continuously along the inner portion of the shell in a circumferential direction, said ribs being formed of a material having higher thermal conductivity than the shell portion disposed outwardly thereof, said shell including an outer shell portion and inwardly extending spaced ribs integral therewith, a liner disposed inwardly of said outer shell portion and in contact therewith, said first named ribs being formed on said liner and respectively enclosing said second named ribs, and said liner having a higher thermal conductivity than said outer shell portion.

References Cited UNITED STATES PATENTS 2,259,024 lO/1941 Cleveland 89 3,241,251 3/1966 Justus et al 34l24 3,367,042 2/1968 COX 34124 KENNETH W. SPRAGUE, Primary Examiner U.S. Cl. X.R. 16589 I 

